WorldDMB GA 2010 Open DAB demonstration - Revision history

Coinchon at 15:30, 7 July 2011

2011-07-07T15:30:48Z

Coinchon at 06:58, 29 October 2010

2010-10-29T06:58:30Z

Coinchon at 16:20, 28 October 2010

2010-10-28T16:20:13Z

Coinchon: /* Scripts */

2010-10-28T12:15:19Z

Scripts

Coinchon: New page: A short demonstration of the creation of a live DAB transmission has been performed after the presentation on local DAB broadcasting. It has been done using a average Dell laptop and were ...

2010-10-28T12:09:14Z

New page: A short demonstration of the creation of a live DAB transmission has been performed after the presentation on local DAB broadcasting. It has been done using a average Dell laptop and were ...

New page

A short demonstration of the creation of a live DAB transmission has been performed after the presentation on local DAB broadcasting. It has been done using a average Dell laptop and were consisting of the transmission of:
*Live sound from the laptop microphone
*Live retransmission of Maxxima webradio
*Live retransmission of France Inter
*Live retransmission of SWR3

Here are the setup and scripts used

===Hardware===
*Dell Latitude E6400 laptop (Centrino 2 CPU)
*USRP1 Universal Software Radio Peripheral with WBX RF daugtherboard (50MHz-2.2GHz)
*[[Filter|Mini-circuits bandpass filter]]

===Software===
*Ubuntu Linux 10.04
*Gnuradio 3.3
*Jack open Audio connection kit
*arecord (from ALSA utils)
*[[Toolame]] open MPEG Layer II encoder
*CRC MMBtools open source DAB multiplexer: [[CRC-DabMux]]
*Non blocking buffer: [http://www.glines.org/software/bfr bfr]
*CRC MMBtools open source DAM modulator: [[CRC-DabMod]]
*[[Band 3 baseband player|Baseband USRP1 VHF player]]

===Scripts===
2 scripts were used in parallel, one for the multiplexer/modulator and the other for getting the sound stream and encode them

Script for stream and encode:
#!/bin/sh

arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug1 |toolame -s 48 -D 4 -b 128 /dev/stdin ./1.ff &
arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug2 |toolame -s 48 -D 4 -b 128 /dev/stdin ./2.ff &
arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug3 |toolame -s 48 -D 4 -b 128 /dev/stdin ./3.ff &
arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug4 |toolame -s 48 -D 4 -b 128 /dev/stdin ./4.ff &

*.ff are FIFO files (names pipes) that were created using "mkfifo" command
*"jackplug" are [http://www.alsa-project.org/main/index.php/Asoundrc#JACK_plugin mapping of jack source to ALSA], defined in .asoundrc file in home directory

Script for multiplexing, encoding, playout:
#!/bin/sh
CRC-DabMux -L "MyMux" -A 1.ff -b 128 -i 1 -S -L "LiveMic" -C \
-A 2.ff -b 128 -i 2 -S -L "Maxxima" -C \
-A 3.ff -b 128 -i 3 -S -L "France Inter" -C \
-A 4.ff -b 128 -i 4 -S -L "SWR3" -C \
-O fifo:///dev/stdout |\
CRC-DabMod -f -g1 -r3200000 |\
bfr -p -b 32m -m 8m |\
coinwap_full3.py

(bfr is the buffer, coinwap_full3.py is the baseband player)

@@ Line 1: / Line 1: @@
-A short demonstration of the creation of a live DAB transmission using a presentation laptop has been performed during the presentation on local DAB broadcasting. It has been done using a average Dell laptop and were consisting of the transmission of:
+A short demonstration of the creation of a live DAB transmission using a presentation laptop has been performed during the presentation on local DAB broadcasting. It has been done using a average Dell laptop and was consisting of the transmission of multiplex of:
 *Live sound from the laptop microphone
 *Live retransmission of Maxxima webradio

@@ Line 35: / Line 35: @@
 *.ff are FIFO files (names pipes) that were created using "mkfifo" command
-*"jackplug" are [http://www.alsa-project.org/main/index.php/Asoundrc#JACK_plugin mapping of jack source to ALSA], defined in .asoundrc file in home directory
+*"jackplug" are  [[mapping of jack source to ALSA]] (or look at http://www.alsa-project.org/main/index.php/Asoundrc#JACK_plugin), defined in .asoundrc file in home directory
 Script for multiplexing, encoding, playout:

@@ Line 33: / Line 33: @@
   arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug3 |toolame -s 48 -D 4 -b 128 /dev/stdin ./3.ff &
   arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug4 |toolame -s 48 -D 4 -b 128 /dev/stdin ./4.ff &
 *.ff are FIFO files (names pipes) that were created using "mkfifo" command
@@ Line 50: / Line 49: @@
 (bfr is the buffer, coinwap_full3.py is the baseband player)